Methods of preparing polyolefin-based materials having improved adhesive/coating compatibility

ABSTRACT

Methods of preparing polyolefin-based molded materials with improved adhesive/coating compatibility by incorporating aromatic carboxylic acid amides and transition metal compounds in the polyolefin-based material prior to molding are described. Methods of producing coated or bonded polyolefin-based, molded materials are also described.

BACKGROUND OF THE INVENTION

Molded workpieces of any three-dimensional form, includingpolyolefin-based moldings, fibers and films, are used on a very widescale in practice. An important problem area here is improving thesurface properties of these structurally nonpolar hydrocarboncomponents. Thus, the poor adhesion of coatings and adhesives is acentral problem which has remained unsolved for decades despite numerousattempts to find a solution.

It is known that the compatibility of plastic surfaces with coatings andadhesives can be improved, for example, by oxidative aftertreatmentprocesses, such as corona or plasma treatment. In processes such asthese, the surface of the plastic is oxidized or chemically modified inthe presence of gases and discharges, so that certain surface propertiesof the plastic can be modified. However, apart from their high energyconsumption, processes such as these always involve an additional stepand lead to ozone emissions in the manufacture of plastic parts. Inaddition, chemical pretreatment processes, including for exampletreatment with fluorine or chlorine gas, with chromosulfuric acid orfluorosulfonic acid, etc., have also been known for some time.

EP-B-372 890 describes polyolefin- or polyester-based fibers with alubricant adhesively applied to their surface. This lubricant comprisesa mixture of (1) fatty acid diethanolamide, (2) a polyether-modifiedsilicone, (3) a sorbitan fatty acid ester and (4) a metal salt of analkyl sulfonate. Components (1) to (4) are present in special quantityratios. According to page 3, lines 20 to 26, the mixture of components(1) to (4) is applied to the surface. The technique by which the mixturecontaining the four components is applied to the surface of fibers isdescribed in detail on page 4, lines 6 to 9. The application techniquesmentioned include a) the use of rollers, b) spraying and c) immersion.Accordingly, the process according to EP-B-372 890 is a process in whicha mixture of components (1) to (4) is applied to the surface ofpolyolefin moldings in an additional process step. Accordingly, theexpression “adhesively applied to the fiber surface” used in claim 1 ofEP-B-372 890 may be clearly interpreted by the expert to mean that anyadhesion involved is loose and temporary, for example in the form ofrelatively weak adhesion forces, and cannot in any way to be consideredto represent permanent anchorage.

In view of the very widely used traditional chemical aftertreatmentprocesses, such as corona and plasma treatment, it is known to theexpert that no exact statements can be made as to the various processesinvolved. However, it has been established that oxidative surfacechanges occur and result in the formation of certain “active centers”.Unfortunately, their concentration generally decreases with time so thatthe pretreatment effect also is only in evidence for a certain time,generally not more than 72 hours (cf. for example, Klaus Stoeckert(Editor), “Veredeln von Kunststoff-Oberflächen”, Munich 1974, page 137).

One feature common to all the known processes is that, in general, thedesired surface effects are only temporarily present.

EP-B-616 622 relates to extrudable compostable polymer compositionscomprising an extrudable thermoplastic polymer, copolymer or mixturesthereof containing a degradation-promoting system of an auto-oxidativecomponent and a transition metal. The auto-oxidative system comprises afatty acid, a substituted fatty acid or derivatives or mixtures thereof,the fatty acid having 10 to 22 carbon atoms and containing at least 0.1%by weight of unsaturated compounds and at least 0.1% by weight of freeacid. The transition metal is present in the composition in the form ofa salt in a quantity of 5 to 500 ppm and is selected from the groupconsisting of cobalt, manganese, copper, cerium, vanadium and iron. Inthe form of a film around 100 microns thick, the composition is said tobe oxidatively degradable to a brittle material over a period of 14 daysat 60° C. and at a relative air humidity of at least 80%.

WO 97/12694 and WO 98/42776 describe the use of amphiphiles forpermanently improving the adhesive and/or coating compatibility ofpolyolefin-based moldings, fibers and films in which a mixturecontaining (a) predominantly one or more polyolefins, (b) one or moremigratable amphiphiles and (c) of one or more transition metal compoundsis subjected in the usual way to molding, for example by extrusion, attemperatures in the range from 180 to 320° C. It is disclosed thatdialkanolamides of unsaturated fatty acids, for example oleic aciddiethanolamide or linoleic acid diethanolamide, are particularlysuitable for use as component (b). So far as the nature of component (c)is concerned, WO 97/12694 makes particular mention of Co, Zr, Fe, Pb,Mn, Ni, Cr, V and Ce while WO 98/42776 refers in particular to Ti and Snas the transition metal present in that component.

BRIEF SUMMARY OF THE INVENTION

The present invention relates, in general, to the use of amides ofaromatic carboxylic acids for permanently improving the adhesive and/orcoating compatibility of polyolefin-based moldings, fibers and films.

The problem addressed by the present invention was to provideauxiliaries with which the adhesive and/or coating compatibility ofpolyolefin-based moldings, fibers and films could be lastingly andpermanently improved. In other words, the object of the invention was toprovide auxiliaries for permanently improving the affinity of polyolefinsurfaces for adhesives and/or coatings. More particularly, the object ofinvention was to make it possible to establish high-strength bonds whichwould rule out unwanted adhesive failures and would ensure that theadhesive joint could only be destroyed by cohesive failure or bycombined cohesive/adhesive failure. In particular, the effectiveness ofthe amphiphiles known from the prior art in permanently improving theadhesive and/or coating compatibility of polyolefin-based moldings,fibers and films would be quantitatively improved.

The present invention relates to the use of carboxylic acid amides forpermanently improving the adhesive and/or coating compatibility ofpolyolefin-based moldings, fibers and films, a mixture containing

a) predominantly one or more polyolefins,

b) 0.01 to 20% by weight—based on the polyolefins—of one or morecarboxylic acid amides and

c) 0.01 to 1000 ppm of one or more transition metal compounds—metalcontent of the transition metal compounds, based on thepolyolefins—being subjected in known manner to molding by extrusion,calendering, injection molding, blow molding and the like attemperatures of 180 to 330° C., with the proviso that the carboxylicacid amides b) are selected from the class of amides of aromaticcarboxylic acids

“Transition metals” in the context of the present invention are anytransition metals in the narrower sense (cf. for example RömppsChemie-Lexikon, Stuttgart 1977, pp. 3717) and, in addition, the metalstin (Sn) and lead (Pb).

The amides of aromatic carboxylic acids b) to be used in accordance withthe invention are derived from aromatic carboxylic acids. These arecompounds which have an aromatic skeleton that may optionally besubstituted by one or more alkyl groups, one or more carboxyl functionsbeing present on this skeleton and/or at the alkyl substituents.

In principle, the aromatic skeleton of the carboxylic acids on which thecompounds b) are based is not subject to any limitations. Thus, thearomatic structural unit of the compounds b) may be derived from benzenealthough it may equally well be derived from a polycyclic compound suchas, for examle, naphthalene, anthracene, etc.

Examles of particularly suitable aromatic carboxylic acids on which thecompounds b) are based are benzoic acid, phthalic acid, terephthalicacid.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment, the compounds b) are characterized by general formula(I):

in which

R¹ is a —(CH₂)_(n)—OH group where n is a number of 1 to 6,

R² is hydrogen, a C₁₋₃ alkyl group or a —(CH₂)_(n)—OH group where n is anumber of 1 to 6,

R³ to R⁷ independently of one another represent hydrogen, a C₁₋₁₂ alkylgroup or a —CONR¹R² group where R¹ and R² are as defined above.

In one embodiment, the total number of —CONR¹R² groups in compounds offormula (I) is at most three. In another embodiment, the total number of—CONR¹R² groups in compounds of formula (I) is at most two.

The compounds (I) may be used both individually and in combination withone another. The compounds mentioned are used in particular in technicalquality.

The compounds b) to be used in accordance with the invention are capableof migration. This means that these compounds are capable of movingduring production, for example by extrusion, to the surface of theresulting polyolefin molding. Accordingly, they accumulate at thesurface of the plastic matrix or in zones near its surface whichApplicants were able to verify by successive removal of surface layersof the order of a few nanometers in thickness and subsequent applicationof Abscan techniques.

The use of the special carboxylic acid amides b) mentioned in accordancewith the invention ensures that coatings and adhesives are able toadhere to the plastic permanently and without additional pretreatment.Once established, adhesive and/or coating compatibility values remainintact for long periods or sometimes even increase in the event ofcontinued storage. According to the invention, there are basically norestrictions as to the type of adhesives and coating compositions whichcan be brought into contact with the polyolefins surface-modified inaccordance with the invention so that permanent bonding or coating isachieved. Thus, any adhesives known to the expert, especiallycommercially available adhesives, may be used as the adhesives. So faras coatings are concerned, paints are particularly relevant. Paints areliquids or powder-form solids which are applied in thin layers tosurfaces and which form a strong decorative and/or protective film onthose surfaces by chemical reaction and/or physical processes. Coatingsin the context of the invention also include printing inks becauseprinting inks are applied to substrates to be printed in a binder layer,adhesion to the substrate being imparted by the binder which forms acoating.

The mixture containing components a), b) and c) is used in traditionalmolding techniques well-known to the expert, such as extrusion,calendering, injection molding and the like. In a preferred embodimentof the present invention, the melt of the mixture containing componentsa), b) and c) comes into contact with oxygen, more especiallyatmospheric oxygen, in the course of the molding process. In the case ofextrusion, for example, this happens when the melt leaves the extruderthrough the extrusion die. The preferred embodiment mentioned aboveenables oxidative—optionally catalytically assisted—processes and othersecondary reactions to take place. (Atmospheric) oxygen can act on theone hand on the surface itself and, on the other hand, even in theinterior of the plastic—especially in zones near the surface—to which itis capable of diffusing.

The combination of the teaching according to the invention which leadsto high adhesive or coating compatibility values with technologies knownper se for improving coating or adhesive compatibility on polyolefinsurfaces falls within the scope of the teaching according to theinvention. Thus, the surfaces of the polyolefins produced in accordancewith the invention may also be both mechanically and chemically and/orphysically treated. However, this is generally not necessary.

As already mentioned, the compounds b) are used in combination withtransition metal compounds c) during the molding of the polyolefins a).The quantity of transition metal compound—metal content of thetransition metal compound based on the polyolefins—is in the range from0.01 to 1000 ppm. Basically, there are no particular restrictions as tothe nature of the transition metal compounds. In principle, therefore,any transition metal compounds known to the expert may be used for thepurposes of the teaching according to the invention. In one embodiment,transition metal salts, preferably salts based on organic acidscontaining 6 to 22 carbon atoms, are used as the transition metalcompounds. In another embodiment, the transition metal compounds areused in a quantity below 5 ppm—metal content of the transition metalcompound based on the polyolefins. Another embodiment is characterizedby the use of transition metal compounds c) of which the metals areselected from the group consisting of Co, Zr, Fe, Pb, Mn, Ni, Cr, V, Ce,Ti and Sn.

If desired, other compounds known to the expert as catalysts foroxidative processes may be used in addition to the compulsory transitionmetal compounds mentioned.

In one preferred embodiment, the ratio by weight of the compounds b) tothe metal content of the transition metal compounds c) is adjusted to avalue of 10:0.1 to 10:10⁻⁷, preferably to a value of 10:0.02 to 10:10⁻⁶and more preferably to a value of 10:0.01 to 10:10⁻⁵.

According to the invention, the special carboxylic acid amides b) areused in the course of routine molding processes, such as extrusion,calendering, injection molding and the like. It may be desirable to usecomponents a), b) and c) in the form of a mixture prepared in advance.Other typical auxiliaries which have generally been successful in themolding of plastics and which are known to the expert, for example slipagents, antistatic agents, lubricants, release agents, UV stabilizers,antioxidants, fillers, fire retardants, mold release agents, nucleatingagents and antiblocking agents, may also be separately made up and addedduring the final mixing of the end products. The common practice ofusing the auxiliaries mentioned in a form in which they are alreadycompletely or partly present in component a) is also expressly includedwithin the scope of the present invention.

However, it may also be desirable, for example where extrusion isapplied, to introduce components b) and/or c) and/or other additiveseither completely or partly into the polyolefin melt itself in theextruder, so that the mixture of components a), b) and c)—and optionallyother auxiliaries—is not present from the outset as a made-up product,but is formed in the extruder itself. A technique such as this isappropriate, for example, when the compounds b) to be added to thepolymer melt are present in liquid form and are easier to inject than tomake up in advance.

It may even be desirable, although not necessary for obtaining theeffect according to the invention, to undertake a conventional corona orplasma treatment after the use of components a) to c) in accordance withthe invention.

Basically, any known ethylene- or propylene-based polymers andcopolymers may be used as the basic oleophilic polyolefin material.

Mixtures of pure polyolefins with copolymers are also suitable inprinciple providing the compounds b) retain their ability to migrate inaccordance with the invention and hence to collect at the surfaces ofsolids. Polymers particularly suitable for the purposes of the teachingaccording to the invention are listed below: poly(ethylenes), such asHDPE (high-density polyethylene), LDPE (low-density polyethylene), VLDPE(very-low-density polyethylene), LLDPE (linear low-densitypolyethylene), MDPE (medium-density polyethylene), UHMPE (ultra highmolecular polyethylene), VPE (crosslinked polyethylene), HPPE(high-pressure polyethylene); isotactic polypropylene; syndiotacticpolypropylene; Metallocen-catalyzed polypropylene, high-impactpolypropylene, random copolymers based on ethylene and propylene, blockcopolymers based on ethylene and propylene; EPM(poly[ethylene-co-propylene]); EPDM(poly[ethylene-co-propylene-co-unconjugated diene]).

Other suitable polymers are: poly(styrene); poly(methylstyrene);poly(oxymethylene); Metallocen-catalyzed α-olefin or cycloolefincopolymers, such as norbornene/ethylene copolymers; copolymerscontaining at least 80% ethylene and/or styrene and less than 20%monomers, such as vinyl acetate, acrylates, methacrylates, acrylic acid,acrylonitrile, vinyl chloride. Examples of such polymers are:poly(ethylene-co-ethyl acrylate), poly(ethylene-co-vinyl acetate),poly(ethylene-co-vinyl chloride), poly(styrene-co-acrylonitrile). Alsosuitable are graft copolymers and polymer blends, i.e. mixtures ofpolymers in which the above-mentioned polymers inter alia are present,for example polymer blends based on polyethylene and polypropylene.

Homopolymers and copolymers based on ethylene and propylene areparticularly preferred for the purposes of the present invention. In oneembodiment of the present invention, therefore, polyethylene on its ownis used as the polyolefin; in another embodiment, polypropylene on itsown is used as the polyolefin and, in a further embodiment,ethylene/propylene copolymers are used as the polyolefin.

The application of coatings or adhesives to the surface-modifiedpolyolefin-based moldings and films obtained by the process according tothe invention may basically be carried out by any of the relevantmethods known to the expert.

In one embodiment, polyethylene is used as component a). If it is HDPE(high-density polyethylene), a temperature of 200 to 300° C. ispreferably adjusted during molding whereas, in the case of HDPEcontaining carbon black, the molding temperature is preferably adjustedto a value in the range from 250 to 300° C. If LDPE (low-densitypolyethylene) is used, a temperature of 180 to 260° C. and moreparticularly in the range from 200 to 260° C. is preferably adjustedduring the molding process.

In the case of extrusion processes, the temperatures just mentioned forHDPE and LDPE apply in particular to the temperature of the die.

If the mixture of components a), b) and c) is molded by extrusion, thepolyolefin molding is cooled by at most 50° C., preferably in 0.1 to 5.0seconds, immediately after leaving the die. Accordingly, thistemperature difference of 50° C.—hereinafter also referred to as ΔT50—isgoverned by the following equation:

ΔT50=T _(die) −T _(polyolefin surface)

where T_(die) is the temperature of the extrusion die whileT_(polyolefin surface) is the surface temperature of the extrudedpolyolefin molding as measured without any contact, for example usingrelevant known infrared techniques (for example with a Chino“IR-TA/Handy 1000” infrared thermometer).

In one particularly preferred embodiment, the polyolefin molding iscooled by at most 50° C. in 1.0 to 5.0 seconds and more particularly in1.7 to 5.0 seconds immediately after leaving the extrusion die.

Assuming that the polyolefin molding moves at a constant speed afterleaving the extrusion die, the time scale mentioned can easily beconverted into a distance scale using the known equation v=s/t(speed=distance divided by time) which can be transformed to s=v * t(distance=speed multiplied by time) from which it can be seen thatdistance s (i.e. distance from the extrusion die) and time t areproportional to one another. By definition, the zero point of thedistance scale is situated immediately at the exit point of the die.

The polyolefin moldings obtainable using the carboxylic acid amides b),more particularly the granules obtainable by extrusion, may be used asso-called master batches in the processing of bulk plastics.

The present invention also relates to a process for the production ofbonded and/or coated polyolefin-based moldings, fibers and films, inwhich a mixture containing

a) predominantly one or more polyolefins,

b) 0.01 to 20% by weight—based on the polyolefins—of one or morecarboxylic acid amides and

c) 0.01 to 1000 ppm of one or more transition metal compounds—metalcontent of the transition metal compounds, based on the polyolefins—issubjected in known manner to molding by extrusion, calendering,injection molding, blow molding and the like at temperatures of 180 to330° C. and the resulting polyolefin-based moldings, fibers and filmswith improved adhesive and/or coating compatibility are subsequentlycontacted in the usual way with an adhesive and/or a coatingcomposition, characterized in that the carboxylic acid amides b) areselected from the class of amides of aromatic carboxylic acids.

EXAMPLES

1. Materials Used

1.1. Polyolefins (a)

Lupo: low-density polyethylene (“Lupolen 1800 H”, a product of Elenac)

1.2. Additives (b)

TDA: terephthalic acid diethanolamide

BDA: benzoic acid diethanolamide

1.3. Transition Metal Compounds (c)

A mixture of cobalt(II) octoate and zirconium(II) octoate was used. Tothis end, a mixture of 4.3 g of a solution of cobalt(II) octoate intoluene (with a cobalt content of 6% by weight), 10.3 g of a solution ofzirconium(II) octoate in toluene (with a zirconium content of 6% byweight) and 10.3 g toluene was prepared. This mixture was used in aquantity of 0.3 g per 600 g component a).

2. Production of Surface-modified Polyethylene by the Process Accordingto the Invention

In order to test the adhesive compatibility properties ofsurface-modified polyethylene, polyethylene was initially produced intape form by mixing

600 g of polyethylene granules a) (the particular type of polyethyleneused is shown in Tables 1 to 3),

additive b) and

transition metal compound c).

The particular type and quantity of components b) and c) used are shownin Table 1. The mixtures were introduced through a hopper into anextruder. A Brabender DSK 42/7 twin-screw extruder (Brabender OHG,Duisburg) was used. As well-known to the expert, an extruder is amachine for processing plastics in which both powder-form and granularthermoplastics can be continuously mixed and plasticized. Beneath thefeed hopper, there is a contra-rotating twin screw longitudinallydivided into three heating zones in addition to a water-cooling systemwhich is intended to prevent premature melting of the granules orpowder. The temperature of the heating zones and the rotational speed ofthe twin screw can be controlled through a data-processing Plast-CorderPL 2000 which is connected to the extruded via a PC interface. Toproduce the polyethylene tapes, the following temperatures wereadjusted: heating zones I-III all 230° C., the three heating zones beingair-cooled to keep the temperatures constant.

The polyethylene granules (including the particular components b) and c)were automatically taken into the extruder by the contra-rotating twinscrew and transported along the screw. The rotational speed was 50r.p.m. This guaranteed a relatively long residence time in the extruderand hence thorough compounding and homogenization. The resultinghomogeneous and substantially bubble-free mixture finally entered a diewhich represents a fourth heating zone. The temperature of the die wasvaried in the individual tests and is shown in Table 1.

After leaving the die, the hot mixture flowed onto a conveyor belt ofwhich the speed was adjusted so that a smooth and uniformly thick andwide tape was formed on cooling in air. In the tests described here, thespeed was adjusted so that the polyethylene tape was about 35 mm wideand about 0.35 mm thick. Square test specimens (25×25 mm) were die-cutfrom this material and used for the bonding tests described hereinafter.

3. Adhesion and Tensile Tests

3.1. Production of the Test Specimens

The extruded tapes produced in accordance with 2) were stored for 24hours at room temperature (20° C.). Square 25×25 mm pieces ofpolyethylene were then bonded between two 100×25 mm strips of wood. Thebond had a thickness of 2 mm. The area bonded measured exactly 25×25=625mm². It is pointed out that the test arrangement corresponds to thatschematized on page 21 of the above-cited WO 98/42776 (except that thepieces of polypropylene was replaced by pieces of polyethylene).

A two-component adhesive (“Makroplast” polyurethane adhesive, a productof Henkel KGaA, Düsseldorf) was used as the adhesive. The two reactivecomponents (resin=UK 8109; hardener=UK 5400) were stirred in a ratio of5:1 in an aluminium dish. The pot life was about 1 hour.

After storage for about 1 hour, 25 mm wide strips were cut off from eachtape and, with the aid of a template, were bonded on both sides betweentwo strips of wood. Five strips of each plastic tape were bonded. Theuse of a template ensures that the required surface to be bonded is keptto between the modified plastic and the strips of wood. Wooden clampswere used to fix the test specimen. Surplus adhesive was removed.

3.2. Tensile Tests

The test specimens produced in accordance with 3.1.) were stored forabout 3 to 4 days at 20° C. to ensure that the two-component adhesivewas fully cured. A Zwick universal testing machine was used to measurethe tensile shear forces. The rate at which the test specimen was placedunder tensile load was 15 mm/min. The bonded wood spatulas (=testspecimens) were clamped in the clamping jaws of the universal testingmachine and pulled apart at the designated test rate. Care was taken toensure that the test specimens were always arranged vertically andexactly in the middle of the testing machine. The test results obtainedare set out in Table 1. All the results are averages of 5 tests.

Explanation of column headings of Table 1:

No. test number (B=invention; C=comparison)

a) component a) (polyolefin)

b) component b); the “%” column shows the quantity in which theparticular compound—% by weight, based on component a)—was used

c) component c); the “ppm Me” column shows the quantity in ppm (partsper million) in which the transition metal of the transition metalcompound—based on component a)—was used

T/die: die temperature in ° C.

TSS: tensile shear strength as determined in the tensile tests andexpressed in newtons/mm²

TABLE 1 b) c) T/die a) % Compound ppm Me Compound ° C. TSS Lupo — — 17.6Co/Zr octoate 250 0.20 Lupo 1.0 TDA 17.6 Co/Zr octoate 250 0.49 Lupo 0.5BDA 17.6 Co/Zr octoate 250 0.99 Lupo 1.0 BDA 17.6 Co/Zr octoate 250 1.79

It can be seen from Table 1 that the results obtained where the amidesof aromatic carboxylic acids according to the invention (cf. Examples B1to B3) are used are distinctly better than those obtained in the absenceof additives.

What is claimed is:
 1. A method of preparing molded polyolefin-basedmaterials with improved adhesive/coating compatibility, said methodcomprising: (a) providing a polyolefin-based material to be molded, saidmaterial comprising one or more polyolefins, from 0.01 to 20% by weightof an aromatic carboxylic acid amide, based upon a total weight of theone or more polyolefins, and a metal compound, wherein the metal isselected from the group consisting of transition metals, lead, and tin,in an amount of from 0.01 to 1000 ppm metal based on the one or morepolyolefins; and (b) subjecting the polyolefin-based material to amolding procedure.
 2. The method according to claim 1, wherein the oneor more polyolefins is selected from the group consisting ofpolyethylenes, polypropylenes, and polyethylene/polypropylenecopolymers.
 3. The method according to claim 1, wherein the one or morepolyolefins comprises a polyethylene.
 4. The method according to claim1, wherein the aromatic carboxylic acid amide corresponds to generalformula (I):

wherein R¹ represents a —(CH₂)_(n)—OH group where n is a number of from1 to 6, R² represents hydrogen, a C₁₋₃ alkyl group or a —(CH₂)_(n)—OHgroup where n is a number of from 1 to 6, and each of R³, R⁴, R⁵, R⁶ andR⁷ independently represents hydrogen, a C₁₋₁₂ alkyl group or a—C(O)NR¹R² group where R¹ and R² are as defined above.
 5. The methodaccording to claim 4, wherein up to two of R³, R⁴, R⁵, R⁶ and R⁷represent a —C(O)NR¹R² group.
 6. The method according to claim 4,wherein up to one of R³, R⁴, R⁵, R⁶ and R⁷ represents a —C(O)NR¹R²group.
 7. The method according to claim 4, wherein the aromaticcarboxylic acid amide is based on an acid selected from the groupconsisting of benzoic acid, phthalic acid, terephthalic acid, andmixtures thereof.
 8. The method according to claim 4, wherein R²represents a —(CH₂)_(n)—OH group wherein n is a number of from 1 to 6.9. The method according to claim 1, wherein the aromatic carboxylic acidamide is selected from the group consisting of terephthalic aciddiethanolamide and benzoic acid diethanolamide.
 10. The method accordingto claim 1, wherein the combined polyolefin-based material, aromaticcarboxylic acid amide and metal compound is molded by extrusion, whereincooling is carried out at a temperature rate of up to 50° C. in from 0.1to 5.0 seconds.
 11. The method according to claim 1, wherein the metalcompound comprises a metal selected from the group consisting of Co, Zr,Fe, Pb, Mn, Ni, Cr, V, Ce, Ti and Sn.
 12. The method according to claim1, wherein the metal compound comprises a transition metal salt.
 13. Themethod according to claim 1, wherein the metal compound is present in anamount of less than 5 ppm metal based on the one or more polyolefins.14. The method according to claim 1, wherein the ratio by weight of thearomatic carboxylic acid amide to the metal compound metal content isadjusted to a value of from 10:0.1 to 10:10⁻⁷.
 15. The method accordingto claim 1, further comprising subjecting the molded, combinedpolyolefin-based material, aromatic carboxylic acid amide and metalcompound to a corona or plasma treatment.
 16. A process for producingbonded and/or coated polyolefin-based moldings, fibers and films, saidprocess comprising: (a) providing a molded polyolefin-based materialprepared by the method according to claim 1; and (b) contacting asurface of the molded polyolefin-based material with a compositionselected from the group consisting of adhesives and coatings.
 17. Amethod of preparing molded polyolefin-based materials with improvedadhesive/coating compatibility, said method comprising: (a) providing apolyolefin-based material to be molded, said material comprising one ormore polyolefins; (b) combining the polyolefin-based material with from0.01 to 20% by weight of an aromatic carboxylic acid amide, based upon atotal weight of the one or more polyolefins, and a metal compound,wherein the metal is selected from the group consisting of transitionmetals, lead, and tin, in an amount of from 0.01 to 1000 ppm metal basedon the one or more polyolefins; and (c) subjecting the combinedpolyolefin-based material, aromatic carboxylic acid amide and metalcompound to a molding procedure; wherein the aromatic carboxylic acidamide corresponds to general formula (I):

wherein R¹ represents a —(CH₂)_(n)—OH group where n is a number of from1 to 6, R² represents hydrogen, a C₁₋₃ alkyl group or a —(CH₂)_(n)—OHgroup where n is a number of from 1 to 6, and each of R³, R⁴, R⁵, R⁶ andR⁷ independently represents hydrogen, a C₁₋₁₂ alkyl group or a—C(O)NR¹R² group where R¹ and R² are as defined above.
 18. A method ofpreparing molded polyolefin-based materials with improvedadhesive/coating compatibility, said method comprising: (a) providing apolyolefin-based material to be molded, said material comprising one ormore polyethylenes, from 0.01 to 20% by weight of an aromatic carboxylicacid amide, based upon a total weight of the one or more polyethylenes,and a metal salt in an amount of from 0.01 to 5 ppm metal based on theone or more polyolefins, wherein the metal salt comprises a metalselected from the group consisting of Co, Zr, Fe, Pb, Mn, Ni, Cr, V, Ce,Ti and Sn.; and (b) subjecting the polyolefin-based material to amolding procedure; wherein the aromatic carboxylic acid amidecorresponds to general formula (I): wherein R¹ represents a—(CH₂)_(n)—OH group where n is a number of from 1 to 6, R² representshydrogen, a C₁₋₃ alkyl group or a —(CH₂)_(n)—OH group where n is anumber of from 1 to 6, and each of R³, R⁴, R⁵, R⁶ and R⁷ independentlyrepresents hydrogen, a C₁₋₁₂ alkyl group or a —C(O)NR¹R² group where R¹and R² are as defined above.